Methods and apparatuses for processing sheets of securities, especially banknotes, into bundles and packs are already known in the art.
As a matter of customary practice, the sheets are processed starting from stacks of hundred sheets, and these stacks are cut along rows and columns between the printed security papers to produce individual bundles of hundred security papers each. Prior to processing of the sheets, the security papers are numbered in such a manner that each bundle contains hundred security papers numbered in sequence. The bundles are banded and further processed to produce packs of, usually, ten bundles, i.e. packs comprising thousand security papers.
Numbering of the security papers is often carried out using mechanical numbering devices that are only adapted to perform incremental or decremental numbering (i.e. the number vary by one increment from one numbering iteration to the next). This implies that the numbering sequence is different for each bundle location in the stack of sheets and that the bundle with the numbering sequence that directly follows that of a given bundle will be derived from the same bundle location in the subsequent stack of sheets. Thus, in order to assemble packs of ten bundles each, one has to process ten successive stacks of sheets and collect all the bundles of a given bundle location within one and a same pocket or magazine. For sheets with M columns and N rows of security prints, one thus needs a so-called bundle collating system with M×N magazines having a storage capacity of ten bundles each.
Depending on the number of security papers on each sheet and on the sheet layout, bundle collating can be simplified to some extent. This is for instance possible when the number of security papers on each sheet is a multiple of ten as disclosed in European patent application No. EP 0 598 679. With this solution, a plurality of bundles with consecutive numbering sequence are located within a same stack of sheets, for instance in each column. Nevertheless, with this solution, one still derives several groups of bundles with different numbering sequences from each stack of sheets, and a collating system is therefore still required. In any case, this solution is not applicable to cases where sheets comprise a number of security prints that is not a multiple of ten.
Non-collating solutions which do not require a collating system are known in the art. With such non-collating solutions, numbering of the sheets has to be carried out in a specific manner that depends on the sheet layout, especially the number of security prints per sheet. This particular numbering principle is disclosed in International application No. WO 2004/016433. With such a numbering principle, all bundles derived from a given stack of sheets correspond to one consecutive numbering sequence, i.e. a stack of sheets with M×N security prints yields M×N bundles numbered in sequence, that is M×N×100 security papers numbered in sequence. The above numbering scheme enabling non-collating processing of stacks of sheets requires specific numbering devices which are usually more expensive than mechanical numbering devices.
Depending on the number of security papers on each sheet and on the sheet layout, mechanical numbering devices can be envisaged to carry out numbering according to the numbering scheme of WO 2004/016433. This is again possible when the number of security papers on each sheet is a multiple of ten (or of twenty-five). One such solution is disclosed in International application No. WO 2005/018945. Another alternate solution is disclosed in European patent application No. EP 1 731 324 in the name of the present Applicant. As before, such solutions are not applicable to cases where sheets comprise a number of security prints that is not a multiple of ten or of twenty-five.
Bundle collating systems are therefore required. Various solutions are known in the art.
U.S. Pat. No. 3,939,621 discloses an apparatus for processing sheets of security prints into bundles and packs comprising a rotary-drum bundle collating system. This bundle collating system comprises two rotating drums each provided with as many magazines as there are security prints on the sheets (i.e. M×N magazines). One drum at a time collects bundles to form packs of bundles in the magazines. When in operation, the drum is rotated with a mean circumferential speed matching that of the conveying means bringing the bundles, so that each bundle of a same stack of sheets is fed successively to a different one of the drum magazines. Once the magazines are filled up with the required number of bundles (i.e. following the processing of ten successive stacks of sheets), the following bundles are fed to the other drum. While the other drum is in operation, the magazines of the first drum are emptied one after the other and the packs are fed to a packaging station. Similar rotary-drum collating systems are further described in U.S. Pat. Nos. 4,045,944, 4,453,707, 4,558,557, and European patent application No. EP 1 607 355.
Another solution is disclosed in European patent application No. EP 0 656 309. This document discloses an apparatus for processing sheets of security prints into bundles and packs comprising a distributor with a rectilinear conveying stage on which all the bundles of a given stack of sheets are transported one behind the other up to predetermined positions above M×N magazines. The conveying stage is provided with a movable bottom which is designed to be opened once the bundles have been appropriately positioned above the magazines to thereby enable the bundles to fall in the magazines. The movable bottom is then closed and a subsequent series of bundles is fed onto the conveying stage, the process being repeated until the magazine are completely filled with bundles. Once the magazines are full, these are emptied by pushing the thus formed packs to the side out of the magazines onto a transport stage running next to the magazines. Other similar distributors with rectilinear conveying stage are also known from British patent application No. GB 2 262 729 and International application No. WO 01/49464.
A problem with the above bundle collating systems resides in the fact that they are dependent on the number of security prints on the sheets and on the sheet layout. Indeed, if the sheets to be processed are changed to sheets with a different number of security prints, the number of magazines has to be changed and the size thereof must be adapted as the size of the bundles changes as well.
In addition, the known collating systems occupy a substantial footprint which gives rise to difficulties when the available space for installation of the finishing equipment is limited.
There is therefore a need for an improved bundle collating system and method.